1. Field of the Invention
This invention relates generally to fabrication systems, and, more particularly, to semiconductor wafer fabrication systems including one or more processing tools through which semiconductor wafers are processed in order to form integrated circuits thereon, wherein when a problem is detected with a processing tool a troubleshooting procedure is initiated to solve the problem.
2. Description of the Related Art
Integrated circuits are typically formed by processing one or more semiconductor wafers as a xe2x80x9clotxe2x80x9d through a series of wafer fabrication tools (i.e., xe2x80x9cprocessing toolsxe2x80x9d). Each processing tool typically performs a single wafer fabrication operation upon the semiconductor wafers of a given lot. For example, a particular processing tool may perform a layering operation, a patterning operation, a doping operation, or a heat treatment upon the semiconductor wafers. A layering operation typically adds a layer of a desired material to an exposed surface of the semiconductor wafers. A patterning operation typically contributes to the removal of selected portions of one or more layers formed by layering. A doping operation typically places dopant atoms upon and within exposed surfaces of the semiconductor wafers, thereby producing p-n junctions required for semiconductor operation. A heat treatment typically heats the semiconductor wafers to achieve specific results (e.g., dopant drive-in or annealing).
Each processing tool typically performs a wafer fabrication operation according to a predefined procedure (i.e., a predetermined set of steps or xe2x80x9crecipexe2x80x9d). For example, a given chemical vapor deposition (CVD) processing tool may carry out a layering operation within a chamber according to a recipe which specifies temperatures and pressures within the chamber as a function of time, as well as the types and flow rates of gases introduced into the chamber.
Characteristics of processed wafers, such as characteristics of key integrated circuit structures formed during wafer fabrication, are typically measured to ensure the characteristics remain within acceptable ranges. In order to detect manufacturing problems as quickly as possible, such measurements are typically performed as soon as possible following critical processing steps. For example, special test structures may be formed on xe2x80x9ctestxe2x80x9d wafers processed along with xe2x80x9cproductxe2x80x9d wafers, or within test areas of the product wafers, and the characteristics of the special test structures may be measured. One common technique for tracking and analyzing manufacturing process variation is called statistical process control (SPC). SPC is typically used to gauge the stability of a manufacturing process over time via charted SPC data (i.e., SPC control charts) which document historical process performance.
When SPC data regarding one or more wafers processed through a given tool indicates a characteristic of the wafers affected by the processing tool has departed from an acceptable range established for the characteristic, an alarm condition may be signaled, and the processing tool may be shut down. In such a situation, a troubleshooting procedure is initiated, the object of which is to clear the alarm condition (i.e., solve the problem) and to return the processing tool to service as quickly as possible.
FIG. 1 is a diagram depicting a typical troubleshooting procedure initiated when a problem with a processing tool is detected (i.e., when a processing tool is subject to an alarm condition). The processing tool may be, for example, a furnace, and the alarm condition may be caused by the fact that a total number of particulate contaminants upon surfaces of wafers processed through the furnace exceeds an SPC upper control limit established for the furnace. When the problem is detected, the processing tool may be shut down due to the alarm condition. Alarm data 100 is presented to a user 102 (e.g., an operator or engineer). In FIG. 1, alarm data 100 is an SPC chart showing that that the total number of particulate contaminants upon surfaces of wafers processed through the furnace exceeds the SPC upper control limit.
Alarm data 100 defines the alarm condition (i.e., the problem with the processing tool). In response to alarm data 100, user 102 may elect to employ a troubleshooting guide (TSG). A TSG represents a systematic method for clearing the alarm condition (i.e., solving the problem) and returning the processing tool to service.
Two of several known types of troubleshooting guides (TSGs) are shown in FIG. 1. A first type of TSG 104 is a textual document divided into sections. Each section may be, for example, directed to a different type or xe2x80x9cclassxe2x80x9d of problem (i.e., xe2x80x9cfault classxe2x80x9d or xe2x80x9cproblem classxe2x80x9d). Each problem class may be directed to a particular type of processing tool and/or a particular application of the particular type of processing tool. Each section of TSG 104 may be divided into subsections, and each subsection may include words describing one or more symptoms of the problem class. A given subsection may also include a probable cause and a corrective action for one or more of the described symptoms, wherein a corrective action is an action which must be accomplished to solve the problem (i.e., to clear the alarm condition). Where the given subsection does not include a probable cause and a corrective action for a described symptom, the described symptom is typically covered in another subsection, and the given section typically directs user 102 to the other subsection.
When employing textual document TSG 104, user 102 must select a section dealing with the problem class indicated by alarm data 100, then read through the subsections of the selected section until a symptom which matches the alarm condition is found. User 102 must then continue to read through the subsections as directed until a probable cause and corrective action corresponding to the symptom are found, then accomplish the corrective action.
A second type of TSG 106 is a flow diagram or flow chart having a single entry or xe2x80x9cstartxe2x80x9d point and multiple steps along multiple paths between the start point and one or more end points. Each end point includes a probable cause for a symptom and a corresponding corrective action which must be accomplished to solve the problem. A path from the start point to a given one of the end points may correspond to a particular symptom. Decision steps of the flow chart are used switch a flow of troubleshooting activity from one path to another. When employing flow chart TSG 106, user 102 must establish a path from the start point to one of the end points, accomplish all required actions along the path, then accomplish the corrective action stated in the end point.
Another known type of TSG is a table having multiple entries. Each entry of the table may include, for example, words describing a symptom, a probable cause for the symptom, and a corrective action which must be accomplished to solve the problem (i.e., clear the alarm condition). Such a tabular TSG may be divided into sections, and each section may be directed to a different problem class as described above. When employing such a tabular TSG, user 102 must select a section of the tabular TSG dealing with the problem class indicated by alarm data 100, read through the symptoms of the table entries until a symptom which matches the alarm condition is found, then take the corrective action associated with the symptom.
It is noted that with all the known types of TSGs described above, the amount of time required to locate a corrective action corresponding to a symptom (i.e., a problem) generally depends on the problem class indicated by alarm data 100 and the length and construction of the TSG.
Alternately, user 102 may elect to use an ad hoc approach 108 to solve the problem as indicated in FIG. 1. For example, faced with the particulate contaminant problem described above, user 102 may elect to clean (or direct the cleaning of) interior surfaces of the furnace in an effort to reduce a number of particulates clinging to interior surfaces of the furnace. Such particulates tend to end up on surfaces of wafers processed through the furnace, contaminating the wafers.
It is noted that reading through symptoms described in a textual document TSG, or establishing a path through a flow chart TSG, can take a long time and can be rather tedious. In view of the objectionable nature of the known types of TSGs described above, many users are tempted to first try ad hoc approach 108. It is noted, however, that ad hoc approach 108 is undesirable as the success of ad hoc approach 108 is greatly dependent upon the knowledge and experience of user 102. An example of ad hoc approach 108 is best described as a xe2x80x9cprocess-of-eliminationxe2x80x9d approach. In the process-of-elimination approach, hardware parts of a tool which may be causing a particular problem are replaced one at a time xe2x80x9c . . . until the problem is solved.xe2x80x9d While this process-of-elimination approach may eventually xe2x80x9csolvexe2x80x9d the problem, many working parts may have been unnecessarily replaced along the way, and far more time than necessary may have been spent in troubleshooting the problem and returning the processing tool to service. In sum, the indeterminate nature of ad hoc approach 108 usually leads to both inefficient use of time and/or resources and increased processing tool down time.
The present invention is directed to a method that may solve, or at least reduce, some or all of the aforementioned problems, and systems incorporating the method.
Several different embodiments of a troubleshooting method are described. In one embodiment of the troubleshooting method, an alarm data image is provided (e.g., to a user). For example, the alarm data image may be displayed upon on a display screen visible by the user. The alarm data image includes an image indicative of a problem (e.g., an abnormal condition or faulty state of a processing or metrology tool). Information indicative of a class in which the problem resides is used to access a corresponding portion of a troubleshooting guide (TSG). The corresponding portion of the TSG includes one or more symptom images, wherein each symptom image includes an image indicative of a symptom of the class in which the problem resides. Each symptom image has a corresponding corrective action. A selected one of the symptom images is selected (e.g., by the user). For example, where the selecting is performed by the user, the user may select one of the symptom images the user believes most closely resembles the alarm data image. The corrective action corresponding to the selected one of the at least one symptom image is provided (e.g., to the user). For example, the corrective action may be displayed upon on the display screen for the user to see. The corrective action may be accomplished (e.g., by the user) to solve the problem.
The alarm data image may be, for example, a two-dimensional (2D) chart or graph, a three-dimensional (3D) chart or graph, or an image or picture. When the alarm data image is a 2D chart or graph, each symptom image in the corresponding portion of the TSG may be a 2D chart or graph. Similarly, when the alarm data image is a 3D chart or graph, the symptom images may be 3D charts or graphs, and when the alarm data image is an image or picture, the symptom images may be images or pictures.
For example, a semiconductor wafer fabrication system may include multiple processing tools. Integrated circuits maybe formed upon semiconductor wafers by processing the semiconductor wafers through the processing tools. In this situation, the alarm data image may include, for example, a two-dimensional (2D) statistical process control (SPC) chart of data regarding a measured characteristic of at least one semiconductor wafer processed through a particular processing tool versus time. The measured characteristic is affected by the particular processing tool. The 2D SPC chart may, for example, indicate the measured characteristic has departed an acceptable range established for the particular processing tool. Each symptom image in the corresponding portion of the TSG may include a 2D SPC chart (e.g., generated from historical data) indicating a different way in which the measured characteristic may depart the acceptable range established for the particular processing tool. The selecting of the selected symptom image may involve selecting the symptom image most closely resembling the alarm data image.
Alternately, the alarm data image may be a 3D chart or graph, and the symptom images may be 3D charts or graphs. Further, the alarm data image may be an image or picture of a condition existing on or within at least one of the semiconductor wafers, and the symptom images may be images or pictures of physical conditions one or more components of the processing tool.
The information indicative of the class in which the problem resides may include, for example, a type of the particular processing tool. The information indicative of the class in which the problem resides may also include an application for which the particular processing tool is being used.
The alarm data image and one or more of the symptom images of the corresponding portion of the TSG may be displayed upon the display screen simultaneously by displaying the alarm data image and the one or more symptom images within different portions of the display screen.
Within the TSG, each symptom image may have a corresponding probable cause in addition to the corresponding corrective action. Following the selecting of the selected symptom image, both the probable cause and the corrective action corresponding to the selected symptom image may be provided (e.g., to the user). For example, both the probable cause and the corrective action corresponding to the selected symptom image may be displayed the upon the display screen (e.g., simultaneously by displaying the probable cause and the corrective action within different portions of the display screen).
A user may select the selected symptom image by moving a pointing device (e.g., a mouse) until an arrow displayed upon the display screen, and representing a positional state of the pointing device, is displayed over the selected symptom image, and activating an electrical switch (e.g., a button of the mouse).
For example, the TSG may be a link-based xe2x80x9chypertextxe2x80x9d (or xe2x80x9chypermediaxe2x80x9d) database in which objects, such as text and graphics, are xe2x80x9clinkedxe2x80x9d to one another. When a displayed first object having a link to a second object is selected, the link is followed and the second object is displayed. The popular World Wide Web is a system of Internet servers that support documents formatted in the hypertext markup language (HTML), wherein HTML supports links between documents, graphics, audio, and video files. Within the TSG, symptom images may be linked to corresponding probable cause and/or corrective actions. When the symptom images are displayed, and one of the symptom images is selected, the link between the selected symptom image and the corresponding probable cause and/or corrective action may be followed, and the corresponding probable cause and/or corrective action may be displayed.
Several different embodiments of a fabrication system are described, each of which incorporates an embodiment of the troubleshooting method. In one embodiment, the fabrication system includes a processing tool, a fault detection engine, a terminal, and a troubleshooting guide (TSG) server. The processing tool acts upon one or more work pieces (e.g., semiconductor wafers) processed through the processing tool, and produces processing tool data during operation. The processing tool data indicates whether the processing tool is operating in a normal state or a faulty state. The processing tool operates in the faulty state only when there is a problem with the processing tool.
The fault detection engine receives the processing tool data and uses the processing tool data to determine whether the processing tool is operating in the normal state or the faulty state. When the processing tool is operating in the faulty state, the fault detection engine provides alarm data to the terminal, wherein the alarm data is indicative of the problem with the processing tool.
The terminal is in communication with the fault detection engine and includes a display screen. The terminal responds to the alarm data from the fault detection engine by displaying an alarm data image upon the display screen, wherein the alarm data image includes an image indicative of the problem with the processing tool.
The TSG server is in communication with the fault detection engine and the terminal. When the processing tool is operating in the faulty state, the TSG server receives information indicative of a class in which the problem with the processing tool resides. The TSG server includes a TSG, and the TSG includes a portion directed to the class in which the problem with the processing tool resides. The portion of the TSG includes one or more symptom images, wherein each symptom image includes an image indicative of a symptom of a problem with the processing tool. The TSG server responds to the information by using the information to access the portion of the TSG and providing TSG data to the terminal, wherein the TSG data conveys the at least one symptom image.
The alarm data provided to the terminal by the fault detection engine may convey the alarm data image. Alternately, the terminal may be configured to generate the alarm data image from the alarm data.
The terminal may be configured to respond to the TSG data from the TSG server by displaying the symptom images conveyed by the TSG data upon the display screen. For example, the terminal may display the alarm data image and the symptom images conveyed by the TSG data within different portions of the display screen such that the alarm data image and the symptom images are displayed upon the display screen simultaneously. Alternately, where the TSG data conveys multiple symptom images, the terminal may display the alarm data image a first portion of the display screen and a portion of the symptom images within a second portion of the display screen. The terminal may display different portions of the symptom images within the second portion of the display screen at different times such that all of the symptom images are eventually displayed upon the display screen.
Within the TSG, each of the symptom images may have a corresponding probable cause and/or corrective action as described above. The TSG server may be adapted to receive selection data indicative of a selected one of the at least one symptom image. The TSG server may respond to the selection data by providing probable cause/corrective action data to the terminal, wherein the probable cause/corrective action data conveys the probable cause and/or the corrective action corresponding to the selected symptom image. The terminal may respond to the probable cause/corrective action data from the TSG server by displaying the probable cause and/or the corrective action upon the display screen.
The fabrication system may be, for example, a semiconductor wafer fabrication system. In this situation, the processing tool may be a deposition tool for depositing a layer of a desired material upon a surface of a semiconductor wafer, a photolithography tool for patterning at least one layer of a photoresist material, an etch tool for patterning at least one layer of a desired material formed upon a surface of a semiconductor wafer, an implant tool for positioning dopant atoms upon or within a surface of a semiconductor wafer, or a furnace for heating a semiconductor wafer.
Within the TSG, each corrective action may include one or more required activities, and the TSG server may be adapted to receive selection data indicative of a selected required activity involving the processing tool. The TSG server may respond to the selection data by sending one or more control signals to the processing tool, wherein the one or more control signals causes the processing tool to accomplish the required activity. Alternately, the fabrication system may include a manufacturing execution system (MES) host in communication with the TSG server and the processing tool. The TSG server may be adapted to respond to the selection data by providing a signal to the MES host. The MES host may respond to the signal by proving the one or more control signals to the processing tool, wherein the one or more control signals causes the processing tool to accomplish the required activity.
When the processing tool is operating in the faulty state, the fault detection engine may be configured to provide a shutdown command to the processing tool. Alternately, the fabrication system may include the MES host described above, and the MES host may be in communication with the fault detection engine. When the processing tool is operating in the faulty state, the fault detection engine may be configured to provide an alarm signal to the MES host. The MES host may respond to the alarm signal by providing the shutdown command to the processing tool.
A semiconductor wafer fabrication system is described including a processing tool, a metrology tool, a fault detection engine, and the terminal and TSG server described above. The semiconductor wafer fabrication system may also include the MES host described above. The processing tool may be, for example, a deposition tool for depositing a layer of a desired material upon a surface of at least one semiconductor wafer, a photolithography tool for patterning at least one layer of a photoresist material, an etch tool for patterning at least one layer of a desired material formed upon a surface of at least one semiconductor wafer, an implant tool for positioning dopant atoms upon or within a surface of at least one semiconductor wafer, or a furnace for heating at least one semiconductor wafer.
The metrology tool is used to measure characteristics of semiconductor wafers previously processed through the processing tool. The metrology tool produces metrology data regarding the processing tool, wherein the metrology data indicates whether the processing tool is operating in a normal state or a faulty state. The processing tool operates in the faulty state only when there is a problem with the processing tool. The metrology tool may also produce metrology tool data during operation, wherein the metrology tool data indicates whether the metrology tool is operating in a normal state or a faulty state. The metrology tool operates in the faulty state only when there is a problem with the metrology tool.
The fault detection engine receives the metrology data and/or the metrology tool data. The fault detection engine uses the metrology data to determine whether the processing tool is operating in the normal state or the faulty state. The fault detection engine uses the metrology tool data to determine whether the metrology tool is operating in the normal state or the faulty state. When the processing tool or the metrology tool is operating in the faulty state, the fault detection engine provides alarm data to the terminal, wherein the alarm data is indicative of the problem with the xe2x80x9cproblematicxe2x80x9d tool (i.e., the processing tool or the metrology tool).
The terminal is in communication with the fault detection engine and includes a display screen. The terminal responds to the alarm data from the fault detection engine by displaying an alarm data image upon the display screen, wherein the alarm data image includes an image indicative of the problem with the problematic tool.
The TSG server is in communication with the fault detection engine and the terminal. When the processing tool or the metrology tool is operating in the faulty state, the TSG server receives information indicative of a class in which the problem with the problematic tool resides. The TSG server includes a TSG, and the TSG includes a portion directed to the class in which the problem with the problematic tool resides. The portion of the TSG includes one or more symptom images, wherein each symptom image includes an image indicative of a symptom of a problem with the problematic tool. The TSG server responds to the information by using the information to access the portion of the TSG and providing TSG data to the terminal, wherein the TSG data conveys the at least one symptom image.
The alarm data provided to the terminal by the fault detection engine may convey the alarm data image. Alternately, the terminal may be configured to generate the alarm data image from the alarm data.